vdb-passwd: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/vdb-passwd - from package: sra-toolkit

You may install the required package with command apt-get install {package}

Error in other languages:
vdb-passwd: bevel nie gevind nie
vdb-passwd: comandă negăsită
vdb-passwd: comando não encontrado
vdb-passwd: commande introuvable
vdb-passwd: command not found
vdb-passwd: käsku ei ole
vdb-passwd: không tìm thấy lệnh
vdb-passwd: komanda nerasta
vdb-passwd: Kommando nicht gefunden.
vdb-passwd: kommandot finns inte
vdb-passwd: komut yok
vdb-passwd: nie znaleziono polecenia
vdb-passwd: níor aimsíodh an t-ordú
vdb-passwd: no se encontró la orden
vdb-passwd: no s'ha trobat l'ordre
vdb-passwd: opdracht niet gevonden
vdb-passwd: parancs nem található
vdb-passwd: perintah tidak ditemukan
vdb-passwd: príkaz nenájdený
vdb-passwd: příkaz nenalezen
vdb-passwd: команда не найдена
vdb-passwd: командата не е открита
vdb-passwd: 命令找不到
vdb-passwd: コマンドが見つかりません